Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond them: the actual phone number is not retrievable by the agent because it is only visible to humans on the website, preventing a false promise of that data.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single dense sentence front-loads what the tool returns, followed by the human-only caveat. Nothing is wasted, though the parenthetical asides make it slightly harder to parse than a clean list.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter, read-only info tool with no output schema, the description covers what content comes back and flags the key limitation. A brief note on the response format would make it fully self-contained, but nothing critical is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, which is the baseline-4 case. There is nothing for the description to clarify beyond the schema, and the description correctly implies a no-argument lookup.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific resource and enumerates its three contents: the phone menu (which button does what), staff availability (working hours), and the identification method. It is clearly distinguishable from generic siblings like get_faq or how_it_works, though it does not name a sibling to route against.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied — an agent infers it should call this when a user asks about phone support. There is no explicit when-to-use/when-not statement and no named alternative among the many sibling tools. The one caveat given (the phone number itself is human-only) partially guides expectations.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.